Impact of Cropping Systems on Macronutrient Distribution and Microbial Biomass in Drought Affected Soils

Abstract. The interplay between soil nutrients, water activity, and microbial biomass is pivotal for plant growth as well as for soil health. While surface microflora typically promotes mineralization and nutrient deposits, the impact of drought on soil microbial biomass and nutrient utilization remains underexplored. In this study, we assessed various land types—open lands (OL), annual crops with single species (ACS), perennial crops with multiple species (PCM), less water available lands (LWA), and soil near ponds (CP)—to elucidate the distribution of macronutrients and microbial biomass. Soil samples were collected from different land types, air-dried, and subjected to physical, chemical, and biological analyses. Standardized protocols, including gravimetric and titration analyses, were employed for physical and chemical assessments, while microbial biomass was evaluated using fumigation. Statistical analyses, including ANOVA and Pearson Coefficient, were employed to discern patterns across seasons, soil depths, and microbial biomass. Microbial biomass carbon (Cmic) ranged from 134.2±1.2 μg/g to 286.6±1.33 μg/g, while nitrogen (Nmic) and phosphorus (Pmic) varied from 11.3±1.3 μg/g to 69.5±0.98 μg/g and 07.6±1.5 μg/g to 77.5±0.6 μg/g, respectively, across all seasons. Carbon stock in the upper soil surface positively influenced nitrogen and phosphorus retention. Notably, PCM exhibited superior Cmic, Nmic, Pmic, and water-holding capacity compared to OL, LWA, and ACS. Our findings underscore the significance of multiple cropping systems, particularly PCM, in enhancing microbial biomass and nutrient levels in drought-affected regions. The observed improvements in soil moisture, nitrogen, phosphorous, and potassium levels suggest that diverse cropping systems can effectively enrich soil nutrients and biomass content in drought stress. In conclusion, our study highlights the potential of perennial crops with multiple species in mitigating the impact of drought on soil microbial biomass and macronutrient distribution. These findings contribute to a deeper understanding of sustainable agricultural practices in drought-prone regions and emphasize the importance of implementing diverse cropping systems to enhance soil health and resilience.